Smoke box associated draft control apparatus



Aug. 16, 1949. R. R. M INTOSH 2,479,502

SMOKE BOX ASSOCIATED DRAFT CONTROL AFPARATUS Filed Sept. 21, 1945 4 Sheets-Sheet l as a7 54 INVENTOR RobertRMcIntosh TORNEY Aug. 16, 1949. R. R. MOINTOSH 2,479,502

SMOKE BOX ASSOCIATED DRAFT CONTROL APPARATUS BY (1.0 M

ORNEY Aug. 16, 1949. R. R. MCINTOSH SMOKE BOX ASSOCIATED DRAFT CONTROL APPARATUS 4 Sheets-Sheet 3 Filed Sept. 21, 1943 Robez fii f Mfintosh U QCPM TORNEY Aug; 16, 1949.

R- R. M INTOSH SMOKE BOX ASSOCIATED DRAFT CONTROL APPARATUS Filed Sept. 21, 1943 4 Sheets-Sheet 4 FTC] 7 fiobewfiflmfiritosh TORNEY Patented Aug. 16, 1949 SMOKE BOX ASSOCIATED DRAFT EONEROL Robert R, McIntosh, -Battle Creek, Mich. eav se g r ee s 21, ..5F;'. P .N9-, 9. ..3$

uolaims- (o1. ng rsa The present invention relates broadly to pres,-

sure regulation, and in its specific phases .it relates more particularly to the regulation of suction pressures in a locomotive smoke box wherein the pressure of the exhaust from the locomotive cylinders through an exhaust orifice of a suction inducing nozzle is controlled, and such controlled pressure in turn is utilized to automatically control, at least over a portion'of its range of operation, an apparatus forregulating the upper suction pressures in-the smoke box.

It has long been standard practicein connection with steam driven locomotives to deliver all, or substantially all, of the .exhaust steam from the cylinders through anexhaust stand in the locomotive front end, andout of the smoke stack to create induced suction pressurein the smoke box and draft through the locomotive to promote combustion inthe fire-box. The back'pressure thus created inthe exhaust standinormallyiincreases approximately .in'stepwith the increase of steam exhausted, and with some locomotives this normal back pressur'e rises to as high as approximately twenty-five pounds per-square inch gage. The induced draft produced in this manner varies approximately in step with't'he back'pressure in the exhauststand, and with the high'back pressures this-induced draftisextreme. -In order to reduce the detrimental effect in the fire box of-the upper 'level-of'the suctionpressure created in this manner, it has been standard practice to install bafiies, partition plates, and netting in the smok'e'bo'x, and to place a long ignition arch in the fire box. The extent --to which this procedurecanbe satisfactorily carried is limited due to itsadverseeffect' on the lower range of suctionpressures, i. e. the greater the baffling, the greater is theamounto'f steam which must be exhausted to create the minimum required suction pressure for efficient and adequate combustion. High suction pressures produced in this manner under normal operating conditions not only reduce the combustion efficiency of the locomotive but also interfere with the uniform burning of 'the 'fire bed. Under high suction pressures, and suction pressures, the products of combustion carry an excessive amount of abrasive material from the fire box-through the me tubes "and smoke box, andthis in turn rapidlywears out the extension, and otherparts which come in contact with-theflow ofproducts ofcombustibh. Three .ways of improving the drafting of a railway locomotive are set'forth in my copend ing patent A5 particularly pulsati high 1.-

. c ..5,0 stay bolt heads, superheater units, smoke stack applications .=Ser. No. 381,290, filed March 1, 1941, which has matured into Patent No. 2,319,916, dated July 10, 1-945; .Ser. No. 428,262, filed Jan. 26, 1 942, which has matured in o Pa e No- 2,377.,895, .dated June 12, 1945; and Ser. No. 461,665., filed .Qctober 1-2; 11942. ThQSe patent applications deal .With multiple ,p ifissure level draftlregulation ;.through ,the,use of one or more air .inlet valvesin thesmcke .ibOX- On y t control back pressure iont ihfiilocomotive cylinclfi fi, and incidenta ly imodi'fy suction ce s re leve in :the smoke ,box,.'1 s setrorth ,in my copending patent ,application ;-,Ser. No. 141,095, .filed April 30, 1942, which has matured into Patent No. 2,3 5, 13, :da ed March :5. 1.9%- As u y 0f the shortcomin s, mificu ties, and m sco ce t on of the prior art lead to the discovery and develop ment ;of the present intention w er i P eifirred rorm, an :air inle means co e at el e ed with an xhaust hack pre u e co trolling mechanism so as to vary the air inlet pressureorera ohs derahler a eap r x mat y instenwith va ia ion i exhau b ck pres u e- A ordinglyhamon the ob cts .of th present invention is theproyisiongof; an improved method and gapparatus zfor icontrolling suction ,pressures.

:Another object is ltotprovide :means for holding suctionlpressuresin :arailroad locomotive smoke box in av substantially ;continuous variable range .normally approximately at .or ,3 net. above the suctionupressiue required (for, highly efficient .oomibustion.

.Another object iis rto ,provide ;.a method vand apparatus for admitting-air. in .controlled. amount into a locomotive smoke :box when .a predeterminedsuction pressurelhas .beenreached therein, and to automatically .control such admission .of ail substantially :step .with .ya'riation's of the back pressure-sleizeliotthe locomotive cylinders as controlled by lathe. back pressure governor.

lAvfurtherpbjecti'is to provide as'uctionpressure .r con'trollin apparatus lwhich may be arranged to operate at variousiprechosen constant or. variableiratio'smtorthe amount of? steam passing through theloomotive c'ylinders orithe 'like.

A furthero bject is to reduce 'slagg ing' of the fire tubes and tube slieetat the'giire b'OXilld of the 1ocofriotii' 'e'i ;A further "Qbiect' is to 'providegan apparatus for controlling mama; "pressure 1 of exhaust steam delivered' froih locoinotiiifcylinders, an" air inlet a paratusgfpr --cb ntrolling the upper I level of the suctianpress'urs' ins-locomot ve smoke box, and

means for connecting said' ba'ek pressure cor;-

" erg 'g ars 2 s isIsa;aggre ate manner such that the two of them cooperate in more efiiciently controlling the suction pressures in the locomotive smoke box.

Still further objects and advantages will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then consists of the steps and means hereinafter fully described and particularly pointed out in the claims, the annexed drawings and the following description setting forth in detail certain means and modes of carrying out the invention, such disclosed means and modes illustrating, however, but several of the various ways in which the principle of the invention may be used.

In said annexed drawings: 4

Figure 1 is a diagrammatic sectional front elevation of a locomotive smoke box showing a preferred form of the present invention as viewed along line ll of Figure 2, looking 'in the direction of the arrows. Figure 2 is a fragmentary diagrammatic side elevation of a locomotive front end with part of the smoke box shell broken away to show a preferred form of the present invention in place.

Figure 3 is a sectional side elevation of a preferred form of back pressure regulating apparatus as takenalong line 3--3 of Figure 4 looking in the direction of the arrows. Figure 4 is a top view of a preferred form of back pressure regulating apparatus as viewed along line 4-4 of Figures 2 and 3 looking in the direction of the arrows.

Figure 5 shows one form of valve guide cage suitable for use particularly as shown in Figures 3 and 7.

Figure 6 is a sectionalcenter elevation of a preferred type of the piston and cylinder assembly which is diagrammatically shown in place in Figures 1 and 2.

Figure 7 shows a fragmentary vertical central elevation of a preferred form of the presure relief valve assembly shown in place in the general assembly illustrated in Figures 1 and 2.

A preferred form of apparatus for carrying out the present invention is diagrammatically shown in the assemblies of Figures 1 and 2. Reference to those figures shows that there is a special form of'exhaust stand -2'mounted within the smoke box for thepurpose of controlling the exhaust steam back pressures. Also mounted in the smoke box is an air inlet apparatus 3 for controlling the upper ranges of the suction pressures therein. Exhaust stand 2 and air inlet apparatus 3 mutually aid each other and cooperate in producing uniform operating conditions, althoughin preferred construction they are suitably connected together so as to more closely control the suction pressure in'smoke box I in accordance with prechosen variations in suction pressure which preferably follow draft requirements quite closely.

The exhaust stand 2 has an upwardly and outwardly flared lower portion 4 which extends upward to a substantially horizontal partition 5 above which is chamber 6, and an auxiliary chamber 1. Partitions 8 and 9 (Figure 4) are used to separate and form two walls of these chambers 6 and I. If desired, partitions 8 and 9 may be omitted and thus leave one large chamber. Horizontal partition 5 is provided with a series of valve seat members II) with valves ll cooperatively seating on same. In the top of the exhaust stand directly above each valve seat is provided an opening l2 into which is threaded- 1y mounted a plug l3. A valve cage l4 (Figures 3 and 5), which is of slightly larger inside diameter than the diameter of valve ll, rests on the outer edge of the top face of valve seat member If] and extends up into opening l2. Plug l3, which threadedly engages opening I2, is adapted to contact the upper end of cage l4 and hold the cage tightly against the upper end of valve seat ID in manner preventing same from working loose under conditions of use. The inner wall l5 of chamber 6 and auxiliary chamber 1 forms a vertical passageway for-the normal upward delivery of exhaust steam which is utilized for creating suction pressure in the locomotive smoke box. Nozzle l 6 is mounted centrally above the passageway formed by inner wall [6 and is held in place in conventional manner. At the outlet end of nozzle i6 is preferably provided a spreader member I! which is anchored in place and utilized to spread the exhaust steam so as to make a seal with the inner face of the smoke stack. The upper portion of nozzle l6 may be made hollow to form a blower ring l8 with a plurality of upwardly directed jets l9, and a live steam inlet pipe 20. Connected to chamber 6 are a pair of outlet pipes 2| and 22. Where an auxiliary chamber 1 is utilized, same will be provided with an outlet pipe 23. Valves II are preferably made of such size and weight relative to the area of opening in valve seat member In that they will remain in closed position until a prechosen back pressure has been created in expansion chamber 24 below horizontal partition 5. The valve then elevates to by-pass part of the exhaust steam and thus aid in maintaining the prechosen back pres sure. The flaring of the exhaust stand to provide an expansion chamber 24 acts to expand and cushion the exhaust from the locomotive cylinders and make the flow of exhaust steam out of exhaust nozzle l6 more uniform. This is of a distinct aid in promoting relatively uniform suction pressures in the smoke box at different rates of steam exhaust from the locomotive cylinders.

Mounted in the upper portion of the smoke box, preferably in front of smoke stack 25, are a pair of tubular inlet members 26 and 21 (Figure 1) which are joined to a center tubular member 28 in substantially air-tight manner according to conventional practice. At the inlet end of members 26 and 21 are respectively mounted closure gates 8| and 82 which are movable endwise on slide members 83 and 84. The closing of these gates renders the air inlet apparatus inoperative and permits the making of repairs to same without interfering with the use of the locomotive. The upper face of tubular member 28 is provided with flanged opening 29, which is preferably circular. Mounted in the upper portion of tubular member 28 is a cross member 353 carrying a suitable bearing 3| substantially central of opening 29. Slidably fitting bearing 3| is a vertically mounted shaft 32 of suitable length which carries valve disc 33 anchored thereto in conventional manner. In order to make disc 33 slide up and down without rotary action, guide pins 85 and 86 (Figure 1) may be joined thereto and slidably fit suitable openings in cross member 30. Valve disc 33 in turn is provided with packing 34 which is adapted to seat on the upper flanged face of tubular member 28 outside of opening 29. This packing 34 may be optionally mounted on the upper flanged face of tubular member 28 in position to seat on the under face of valve disc 33, and the drawing is intended to diagram atically iilustreteeitber of construction. The upper end of lshaft 32'extends through a suitable opening in a removable pan member 35which s preferably flanged and conventionally connected to ,asuitable flanged member 36 extending in air-tight manner upward from thetop of smoke box Mounted on pan 35 is-a plate member .31 on which ,ismounted a cylinder 38 (Figure 6) with upper and lower cylinder heads 39 and .40. Shaft 32. extends through the lower cylinder head 40 in conventional manner and has a, piston 4| mounted on the upper end thereof. To facilitate this shaft .32 is provided with a rounded knob end connected to shaft 32 by means of a short reduced diameter extension member 43. The use ofa rounded knob endconnection for the piston 'faciL- itates alignment of the Piston in the cylinder, and also the removal of the piston from the top of the cylinder for-cleaning or other purposes. Piston 4| has an opening through its upper end which is of a sufficient size to permit the passage of knob end 42 therethrough. The extension member 43 in this case should be long enough to permit knob end 42 to be p ssed sufliciently up through the hole in the upper end of piston 4| so that a suitably slit or multiple-piece ring 44 can be placed under knob end 42 in recess 45. A cap 46 shaped to fit knob end 42 is then tightened down in place to the body 41 Of, piston by means of cap screws 48, or the like, with suflicient clearance to permit movement of the knob end for alignment of the piston in the cylinder, Upper cylinder head 39 is preferably provided with a threaded Opening 49 adapted to threadedly en-. gage pipe 50 for a purpose to be hereinafter described. In order to reduce frictional loss the piston is preferably provided with circumferential grooves 81 which fill with liquid to produce a piston ring eifect. Admin 88 in lower cylinder head 40 is provided topermit escape of any liquid which by-passes piston 4|.

Connected to the expansion chamber 24 of exhaust stand 2 is a suitable connection to which is threadedly joined a nipple 52. A ground joint coupling 53 connects nipple 52 to pipe 54 which extends to a pipe T 55, one outlet from which is connected to pipe 50 at the top of cylinder 38 by means of nipple 56, ground joint coupling 51, pipe 58, elbow 59, pipe 60, elbow 5|, pipe 62, elbow 63, nipple 64, ground joint coupling 65, pipe 66, and elbow 61. The second outlet from pipe T 55 may be closed if desired, and in that case, any increase or decrease in back pressure in expansion chamber 24 of exhaust stand2 will directly vary the pressure exerted on he t of piston 4| in cylinder 38 and thusdirectly affect the loading of valve disc :33 with corresponding variation of the suction pressure in the smoke box at which valve disc 33 will open to admit a suction reducing gaseous fluid such as air. The ratio of loading the valve disc 33, and consequently the rate of increase in the suction pressure controlled by the disc can be varied by varying the size of cylinder 38, i. .e. a glvenrisein back pressure in expansion chamber 24 will produce increased loading of the disc when the cylin-w der is larger.

If a controlled upper pressure is to be. exerted on the top of piston 4| in cylinder 38 a thing which willsubstantially prevent further increase in the suction pressure in the smoke box, a suitable pressure relief assembly 68 (Figures 1,2 and 7) may beused. The constructicnot this press e i f as m ly is as follow .Pipe T 5- 8 connected by means of pipe 89 to the bottom oi housing 10 (Figure 7) of pressure relief assembly 68. In preferred construction, housing 1|] is provided with a partition 1| forming a chamber 12 in thebottorn of pressure relief assembly 168. Threadedly fitting a suitable opening through partition 1| is a valve seat member 13 which on operates with valve 14 to form a closed joint at pressures in chamber 12;below a prescribed level. This-pressure is predetermined and valve 14 made of a suitable weight to start rising when this pressure is reached in chamber 12. A valve cage 15, which may be made of the same general construction as valve cage I4 shown in Figure 5, is adapted to pass through a suitable opening 16 in the top of housing 10. This opening is preferably threaded and a plug 11 utilized to close same, and at the same time hold valve cage .15 against the top of valve seat member 13 to prevent same from coming loose under conditions of use. Nipple 18, ground joint coupling 19, and nipple serve to connect the interior of relief assembly 68 to the atmosphere, and for convenience'nipple 8!! may be connected to outlet pipe 22 for outlet therethrough of any steam which flows into the upper portion of housing 10 due to the raising of valve 14 from valve seat member 13 under influence of steam pressure in chamber 12.

The back pressure in expansion chamber 24 may be relatively closely governed by predetermining the weight of valves The valves in chamber 6 may be all of the "same weight, if desired, a thing which will produce a substah tially single upper pressure level for the back pressure in expansion chamber :24 of the exhaust stand. Any increase of the amount of steam exhausted from the locomotive cylinders 89 will require a'correspondingly greater generation of steam. This in turn calls for increased draft suction pressure which can be accomplished by varying the weight of valves so that some will open at a prescribed back pressure and others will open at a higher backpressure or pressures, thus giving a gradual rise in back pressure in expansion chamber 24 as the valves become progressively subjected to steam pressures in excess of their capacity to control. Auxiliary chamber 1, where same is utilized, may be adapted to go into operation under certain prescribed conditions, and may have valves therein set to meet ,a-prescribed back pressure situation. For instance, they may act as overload valves to hold the back pressure in expansion chamber .34 from rising above a prescribed upper level. A valve 90 may be connected to outlet pipe 23, and this valve may be used to permit or prevent any exhaust flow from auxiliary chamber 1. e i a In actual operation, the maximum and mini-'- mum draft requirements for a locomotive are predetermined and then the weight of valve disc 33, shaft 32, guide pins and 86, and piston assembly 4| are adjusted so that valve disc 3| will start to raise and admit suction reducing air into smoke box I through opening 29 at the point where the desired minimum operating suction pressure has been reached. The raising of the back pressure incident to increased steam consumption will cause fluid pressure to be exerted through the pipe connections to the top of piston assembly 4| and thus additionally load valve disc 33 and increase the suction pressure in the smoke box according to a predetermined ratio, preferably instep with. the increased steam generation requirements. s

This arrangementpermits the reduction of the dischargeoriflce area in nozzle I 6 substantially below the area normally used so that a relatively small amount of exhaust steam discharged through the nozzle will create the minimum back pressure desired and produce relatively higher suction pressures and provide for efflcient combustion even under low steam demand conditions. From this point on the valves in the exhaust stand control the back pressure in accordance with a predetermined plan so that with increased steam consumption the back pressure will increase at a predetermined rate and thus effect in like manner the loading of disc 33 as previously explained. Such loading may thus be varied to agree with a predetermined range of suction pressures which will meet therequirements of drafting the locomotive. Controlling suction pressures in this manner not only makes possible highly efilcient operation so'iar as combustion, and increased mean efiecti'vepressures on the driving cylinders are concerned, but it also decreases slagging of the tubes and the firebox tube sheet. The latter advantage, it is believed, is due to the fact that suction pressures, when utilizing the present invention, are readily held at the minimum predetermined level even under light operating conditions, and this in turn provides suflicient draft to maintain higher temperatures in the fire box while reducing or substantially eliminating the clinkering and fusing'of the ash in the fire bed as a result of the more constant and increased flow or air therethrough. Then by controlling the upper suction pressures so as to be just slightly in excess of the maximum required for eflicient combustion, the possibility of increased suction pressures causing the carrying of molten slag, if any is produced, over the arch and against the tube sheet, to which it will promptly adhere and eventually plug over the tube openings on the fire box end, is materially reduced. The absence of violent pulsations in the flow of the products of combustion, due to the use of the back pressure governor and air inlet apparatus in' the smoke box, materially contributes to this result.

Other modes of applying the principle of my invention may be employed instead of those ex plained, change being made as regards the means and steps herein disclosed, provided those stated by any of the following claims or their equivalent be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In an apparatus of the character described, the combination which comprises Walls forming a chamber wherein pressure is to be controlled, an inlet thereinto, an outlet therefrom, means having a passageway of fixed size flow area, for directing a gaseous fluid flowing under pressure out through said outlet to produce suction pressure in said chamber by injection effect, selfcontained means adjacent said passageway and within the confines of said chamberfor controlling the upper pressures of said gaseous fluid in said means for delivering same through said outlet from said chamber, means for admitting suction reducing gaseous fluid into said chamber when the suction pressure produced therein by the flow of controlled pressure fluid directed through said outlet exceeds a predetermined amount, and pressure responsive means connecting said means for delivering a gaseous fluid through said outlet to said means for admitting suction reducing gaseous fluid into said chamber so as to vary the gaseous fluid admission over the latter, over at least a substantial range of its op- 8 oration, approximatelyinversely to pressure variations in the former. I

2. In an apparatus of the character described, the combination which-comprises walls forming a chamber wherein pressure is to be controlled, an inlet thereinto, an elongated outlet member extending from the interior to the exterior of said chamber, meanshaving a passageway of fixed size flow area for directing a gaseous fluid flowing under pressure out through said elongated member in manner such that said gaseous fluid forms a circumferential seal with the inner surface of said elongated outlet member and produces a suction pressure in said chamber by injection efiect, self contained means adjacent said passageway and within the confines of said chamber for controlling the upper pressures 01' said gaseous fluid in said means for delivering same through said outlet means from said chamber, means for admitting suction reducing gaseous fluid into said chamber when the suction pressure produced therein by the flow of controlled pressure fluid directed through said outlet exceeds a predetermined amount, and pressure responsive means connecting said means for delivering a gaseous fluid through said elongated member, to said means for admitting suction reducing gaseous fluid into said chamber so as to vary the gaseous fluid admission of the latter, over at least a substantial range of its operation, approximately inversely to pressure variations in theformer. g 3. In an apparatus or the character described, the combination which comprises walls forming a chamberin which a reduced pressure exists, an inlet thereinto and an outlet therefrom, a duct communicating withasource of higher pressure fluid, said duct having an outlet into said chamber, a valve for said outlet, a cylinder, a piston in said cylinder, means for connecting said piston to said valve for movement in unison therewith, and means connected to said cylinder ior applying a second fluid under pressure to said piston in controlled amount for determining the opening point of said valve which maintains a controlled upper limit of fluid pressure in said chamber. 7 4. An apparatus for controlling pressure in a walled chamber, which comprises, an inlet and an outlet from said chamber, means for forcibly deliveringa gaseous fluid out through said outlet to produce reduced pressure in said chamber by injection effect, means for controlling the pressure in said gaseous fluid delivering means, means'having a valve'ior admitting suction reducing gaseous fluid into said chamber when the suction pressure therein exceeds a predetermined amount, and means including a cylinder with piston and -a tubular member connecting said cylinder to said gaseous fluid delivering means, the pistonofsaid'cylinder being conventionally connected to the'valve'of said means for admitting suction reducirig gaseous fluid into said chamber, whereby the pressure in said first gaseous fluid'delivering means is used to vary the opening'lof said valve for admitting suction reducing gaseous fluidintosaid chamber with re sultant control of the pressure therein at which said suction reducing gaseous fluid is admitted thereinto. 4

' 5. An apparatus for controlling pressure in a walled chamber, which comprises an inlet means, an elongated tubular outlet member extending from theinjterionto the 'exterior of said chamber, means -forforcibly delivering gaseous fluid out through said elongated outlet member in manner such that said gaseousfluid forms a cir cumferential seal with the inner surface of. said.

elongated outlet member and produces. a suction pressure in said chamber by injection effect, means for controlling the-pressuresin said means for delivering gaseous fluid through said outlet means from said. chamber, means having a valve for admitting suctionreduclng gaseous fluid into said chamber when the suction pressure therein exceeds a predetermined amount, andmeans including a cylinder with piston. and a tubular member connecting said cylinder to said gaseous fluid delivering means, the piston of said cylinder being conventionally connected to the valve. of said means for admitting suction reducing gaseous fluid into said chamber, whereby the pressure in said fi'rstgaseous fluid delivering means is used to vary the opening of said valve for admitting suction reducing gaseous fluid into said chamber withresultant control of the pressure therein at which said suction reducing gaseous fluid is admitted thereinto.

6. An apparatus for controlling pressure in a walled chamber, which comprises an inlet means for flow of fluid into said chamber, an elongated tubular outlet member extending from the interior to the exterior of said chamber, means for forcibly delivering gaseous fluid out through said elongated outlet member in manner such that said gaseous fluid forms a circumferential seal withthe inner surface of. said elongated outlet member and, produces. a suction pressure in said chamber by injectioneflect, means for controlling the pressures in saidmeans for delivering gaseous fluid through said outlet. means from said cham ber, means for admitting suction reducing gaseous fluid into said chamber when the suction pressure therein exceeds a predetermined amount, said gaseous. fluid admitting means including an inlet duct, with outlet therefrom, a valve disc for closing said outlet, a cylinder, a. piston in said cylinder, and means for connecting said piston to said valvedisc in manner permitting movement of said valve disc to and from said outlet, and means for. connecting said gaseous fluid delivering means to said cylinder of said means for admitting suction reducing gaseous .fluid into said chamber, whereby the pressure in said gaseous fluid delivering means is used to control the pressure. in said chamber at which said suction. reducing. gaseous. fluid is admitted thereinto.

7. An aparatus for controlling pressure in a walled chamber, which comprises an inlet means for flow of fluid. into said. chamber, an elongated tubular outlet member extending from the interior of the exterior of said chamber, means for forcibly delivering gaseous fluid. out through said elongatedv outlet member in manner such that said gaseous fluid forms a circumferential seal with the inner surfaceof said elongated outlet member and produces a suction pressure in said chamber by injection eliect, means for controlling the pressures in said, means for deliver- I ing gaseous fluid through said outlet means from said chamber, said pressure controlling means including at least one valve which opens to divert part of said gaseous fluid when the fluid pressure in said means for forcibly delivering gaseous fluid out through said. elongated outlet member exceeds a predetermined level, means for delivering said diverted portion of said gaseous fluid to a point of disposal, whereby the pressure in said means for forcibly delivering gaseous fluid controlled, means for admitting, suction reducing. gaseous fluid into said chamber when the suction pressure. therein. exceeds a predetermined amount, and means connecting said gaseous fluid delivering means to said means for admitting suction reducing. gaseous fluid into said chamber, whereby the. pressure in said gaseous fluid delivering means is. used. to control the pressure in said chamber at which. said suction reducing gaseousfluid is admitted thereinto.

8. An apparatus for controlling pressure in a walled chamber, which comprises an inlet means for flow of fluid into said chamber, an elongated tubular outlet member extending from the interior to the exterior of. said chamber, means for forcibly delivering gaseous fluid out through said elongated outlet member in manner such that said. gaseous fluid forms aoircumferential seal with the inner surface of said elongated outlet member and produces. a suction pressure in said chamber by injection efiect, means for controlling the pressures in said means for delivering gaseous fluid through said. outlet means from said chamber, said pressure controlling means including at least one valve which opens to divert part of said gaseous fluid when the fluid pressure in said means for forcibly delivering gaseous fluid out through said. elongated outlet member exceeds a predetermined. level, means for delivering said diverted portion of said gaseous fluid. to a point of disposal, whereby the pressure in said means for forcibly delivering gaseous fluid is controlled, means for. admitting suction reducing gaseous fluid into said chamber when the suction pressure therein exceeds a predetermined amount, said gaseous fluid admitting means including an inlet duct with outlet therefrom, a. valve disc for closing said enact, a cylinder, 2. piston in said cylinder, and. mea s for connecting said piston to said valve. disc in manner permitting movement of said. valve disc to and from said. outlet, and. means. for connecting said gaseous fluid delivering meansto said cylinder of said means for admitting. suction. reducing gaseous fluid into said chamber, whereby the pressure in said gaseous fluid delivering means is used to control the pressure in said chamber at whichsaid suction reducing gaseousfiuid is admitted thereinto.

9. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box, a smoke stack. extending therefrom, a fire box, and. passageways for delivering smoke from the fire box to the smoke box, which comprises the combination therewith or means with a. fixed area passageway for delivering steam exhausted from said driving cylinders out through said smoke stack to create induced suction pressure in said smoke box, self-contained means within the confines or said smoke box for controlling the upper pressure or said exhaust steam in said delivering means before delivery therefrom, means for admitting a suction reducing gaseous fluid into said smoke box when the suc-' Operation. it. is directly in step with variations in 11 l A the upper pressure of said exhaust steam in said delivering means.

10. In a railroad locomotive which has driving cylinders, a smoke box, an inlet and an outlet from said smoke box for products of combustion, a governor for the exhaust back pressure on the driving cylinders, and a valve controlled inlet to said smoke box for a suction pressure reducing gaseous fluid, the combination which includes a variable loading means connected to said valve covering the suction pressure reducing gaseous fiuid inlet to said smoke box, and pressure responsive means connected to said back pressure governor and to said variable loading means for varying the loading of said inlet valve directly in step with variations in the governed exhaust back pressure.

11. An apparatus for controlling draft through a railroad locomotive having driving cylinders, asmoke box, a smoke stack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which comprises the combination therewith of means for delivering steam exhausted from said driving cylinders out through said smoke stack to create suction pressurein said smoke box, means for controlling the pressure of said exhaust steam in said delivering means, a valve controlled inlet to said smoke box for a suction pressure reducing gaseous fiuid, a cylinder with piston and piston rod, said rod being connected to said valve, and tubular means for operatively connecting said means for delivering exhaust steam into and through the smoke stack to the cylinder connected for variably loading the valve of said means for admitting suction reducing gaseous fluid into said smoke box, said connecting means utilizing the pressure in said exhaust steam delivering means to control the suction reducin gaseous fluid admitting means so that it admits suction reducing gaseous fluid into said smoke box when the suction pressure therein is in excess of a predetermined level.

12. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box, a smokestack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which comprises the combination therewith of means having a passageway of fixed size flow area for delivering steam exhausted from said driving cylinders out through said smoke stack to create suction pressure in said smoke box, valve means adjacent said fixed size flow area passageway for controlling the pressure of said exhaust steam therein by bleeding off a portion of same under conditions where the exhaust steam back pressure exceeds a predetermined minimum, means for delivering said bleed-ofi portion to a point of disposal, means for admitting a suction reducing gaseous fluid into said smoke box when the suction pressure therein reaches a predetermined level, said means for admitting a, suction reducing gaseous fluid including an inlet duct with outlet therefrom into said smoke box, and a movable valve disc for closing said outlet, said valve disc having a variable loading means so that said valve may elevate from said outlet and admit a controlled amount of suction reducing gaseous fluid into the smoke box under predetermined suction pressure conditions therein,

- and means connected to said fixed area passageway and to said variable loading means for variably loading the latter directly in step with pressure variations in said fixed area passageway.

13. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box,a smoke stack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which comprises the combination therewith of means having a passageway of fixed size flow area for delivering steam exhausted from said driving cylinders out through said smoke stack to create suction pressure in said smoke box, valve means adjacent said fixed size fiow area passageway for controlling the pressure of said exhaust steam therein by bleeding off a portion of same under conditions where the exhaust steam back pressure exceeds a predetermined minimum, means for delivering said bleed-oil portion to a point of disposal, means for admitting a suction reducing gaseous fluid into said smoke box when the suction pressure therein reaches a, predetermined level, said means for admitting a suction reducing gaseous fluid including an inlet duct with outlet therefrom into said smoke box, and a valve disc for closing said outlet, said valve disc being suitably loaded so as to open said outlet and admit a suction reducing gaseous fluid into the smoke box under predetermined suction pressure conditions, a cylinder with piston and piston rod, said piston rod being connected to said valve disc for further loading same in variable manner, and tubular means for connecting the fixed area passageway of said gaseous fluid delivering means to the cylinder connected to said valve means for admitting a suction reducing gaseous fluid into said smoke box, whereby the pressure of the exhaust steam in said means for delivering exhaust steam through the smoke stack is used through said connecting means to control the suction pressure in said smoke box at which said means ior admitting suction reducing fluid opens to admit suction reducing gaseous fluid thereinto.

14. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box, a smoke stack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which comprises the combination therewith of means for delivering steam exhausted from said driving cylinders out through said smoke stack to create suction pressure in said smoke box, valve means for controlling the pressure of said exhaust steam in said delivering means by bleeding oil a portion of same under predetermined conditions, means for delivering said bleed-oi. portion to a point of disposal, means for admitting a suction reducing gaseous fluid into said smoke box when the suction pressure therein reaches a predetermined level, said means for admitting a suction reducing gaseous fluid including an open end inlet duct with outlet therefrom, a valve disc for closing said outlet, a cylinder, a piston in said cylinder, and means for connecting said piston to said valve disc in manner permitting and controlling the movement of said valve disc to and from said outlet, and means for connecting said exhaust steam delivering means to said cylinder of said means for admitting suction reducing gaseous fluid into said chamber, whereby the exhaust steam pressure in said exhaust steam delivering means is used to control the pressure in said chamber at which said suction reducing gaseous fiuid is admitted thereinto.

15. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box, a smoke stack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which comprises the combination therewith of means for delivering steam exhausted from said driving cylinders out through said smoke stack to create suction pressure in said smoke box, valve means for controlling the pressure of said exhaust steam in said delivering means by bleeding off a portion of same under predetermined conditions, means for delivering said bleed-off portion of said exhaust steam to a point of disposal, means for admitting a suction reducing gaseous fluid into said smoke box when the suction pressure therein reaches a predetermined level, said means for admitting a suction reducing gaseous fluid including an inlet duct with outlet therefrom, a valve disc for closing said outlet, a cylinder, a piston in said cylinder, and means for connecting said piston to said valve disc in manner permitting and controlling the movement of said valve disc to and from said outlet, and a tubular means connected to said exhaust steam delivering means at one end and to said cylinder at the other, whereby variations in pressure in said exhaust steam delivering means will be transmitted to and applied on said piston which in turn, through its connection to said valve disc, will vary the loading on the latter and will correspondingly vary the suction pressures in the smoke box at which same will open.

16. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box, a smoke stack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which oomprises the combination therewith of means for delivering steam exhausted from said driving cylinders out through said smoke stack to create suction pressure in said smoke box, valve means for controlling the pressure of said exhaust steam in said delivering means by bleeding off a portion of same under predetermined conditions, means for delivering said bleed-off portion of said exhaust steam to a point of disposal, means for admitting a suction reducing gaseous fluid into said smoke box when the suction pressure therein reaches a predetermined level, said means for admitting a suction reducing gaseous fluid including an inlet duct with outlet therefrom, a valve disc for closing said outlet, a cylinder, a piston in said cylinder, and means for connecting said piston to said valve disc in manner permitting and controlling the movement of said valve disc to and from said outlet, a tubular means connected to said exhaust steam delivering means at one end and to said cylinder at the other, whereby variations in pressure in said exhaust steam delivering means will be trans mitted to and applied on said piston which in turn, through its connection to said valve disc, will vary the loading on the latter and will correspondingly vary the suction pressures in the smoke box at which same will open, and valve means connected to said tubular means for predetermining the upper limit of pressure which will be applied to said piston.

17. An apparatus for controlling draft through a railroad locomotive having driving cylinders, a smoke box, a smoke stack extending therefrom, a fire box, and passageways for delivering smoke from the fire box to the smoke box, which consists of the combination therewith of an exhaust stand, means for conducting exhaust steam from said cylinders to said exhaust stand, said exhaust stand having an expansion space, a substantially central upwardly directed passageway, a nozzle at the outlet end thereof, a chamber around said upwardly directed passageway, a substantially horizontal bottom panel for said chamber, a series of valve seat members in said bottom panel, a valve of predetermined size in said chamber for each of said valve seat members, means for guiding said valves to and from said valve seat mem bers, and outlet connections from said chamber; means for admitting air into said smoke box when the suction pressure therein reaches a predetermined level, said air inlet means consisting of a relatively large duct normally open to the atmosphere at least at one end and provided with a substantially horizontal outlet on its upper face, a valve disc for said outlet, means for making a substantially tight fit between said disc and the upper face of said duct when said disc is in place over said outlet, a rod on which said disc is fastened, guide means for said rod, means for guiding said disc in a longitudinal direction, a cylinder, means on which said cylinder is mounted, a piston in said cylinder, said piston being fastened on one end of the rod on which the valve disc is fastened; and a tubular means connecting the expansion space of the exhaust stand to said cylinder, whereby any increase in pressure in the expansion space will increase the pressure in the cylinder and thus increase the loading on the valve disc with consequent increase in the suction pressure in said smoke box at which the valve disc will elevate and admit suction reducing air thereinto.

ROBERT R. McINTOSI-I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 157,201 Gregory Nov. 24, 1874 655,405 Luttgens Aug. 7, 1900 678,113 Everson July 9, 1901 702,005 Horenz June 10, 1902 1,131,036 Burke Mar. 9, 1915 1,139,350 Dansbrook May 11, 1915 1,148,342 Staats July 27, 1915 1,333,861 McCarroll Mar. 16, 1920 1,452,210 Myers Apr. 17, 1923 1,458,540 Myers June 12, 1923 1,458,766 Kohn June 12, 1923 2,222,502 Bertram Nov. 19, 1940 Certificate of Correction Patent N 0. 2,479,502 August 16, 1949 ROBERT R. McINTOSH It is hereby certified that error appears in the printed specification of the above numbered patent requiring correctlon as follows:

Column 7, line 74, for the words over the read of the;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice. Signed and sealed this 17th day of January, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

